Back bar linkage assembly

ABSTRACT

A linkage for mounting the elements of an in-line pipeline inspection vehicle. The embodiment allows measurements to be taken while constraining the vehicle to travel within an axial plane of the pipeline.

RELATED APPLICATIONS

This application claims the benefit of co-pending U.S. ProvisionalPatent Application Ser. No. 61/065,462 filed Feb. 11, 2008.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is the side view of a system of the embodiment.

FIG. 2 is a side view of the embodiment.

FIG. 3 is an exploded view of the embodiment.

FIG. 4 is an exploded view of the front linkage of the embodiment.

FIG. 5 is an exploded view of the rear linkage of the embodiment.

DETAILED DESCRIPTION OF THE EMBODIMENT

Elements of the embodiment are:

1 odometer wheel

2 polyurethane supporting and driving cup

3 power canister

4 flexible coupler

5 ID-OD discrimination sensors

6 electronic component canister

7 magnets

8 sensor heads

9 magnetic assembly body

10 linkage assembly

11 magnetic back bar

12 magnetic back bar linkage mount

13 front linkage mount

14 front mid link

15 rear mounting link

16 rear plate side link

17 rear backside link

18 hinge pin

19 locking snap ring

Referring to FIG. 1, a magnetic flux leakage pipeline inspection vehicleis shown in accordance with the embodiment. The vehicle comprises acanister containing a power source 3, a canister containing a dataacquisition and computation system 6 and a magnetic assembly body 9 towhich the magnets 7 and the primary sensor head assemblies 8 areattached. Depending upon the configuration of the in-line inspectionvehicle and the size of the pipeline to be inspected, there may be moreor fewer canisters. The embodiment uses magnets 7 and sensors 8 toidentify pipeline anomalies, odometer wheels 1 to locate anomalies inthe pipeline wall, and polyurethane cups 2 to support and propel thevehicle in the pipeline. The canisters are attached by flexible couplers4.

As shown in FIG. 2, the embodiment comprises a back bar 11 which holdsmagnets 7 and sensor heads 8 and a back bar linkage assembly 12. Thefront end of the back bar 11 and linkage mount 12 has a front mid link14 and a front linkage mount 13 that is fastened to the magneticassembly body 9. The front and rear ends of the back bar 11 have alinkage mount 12. The rear linkage has a rear backside link 17, a rearplate side link 16, and a rear mounting link 15 to complete the rearlinkage assembly. The combined rear plate side link 16 and rear backsidelink 17 allow both radial translation and rotation in an axial planewhile confining the assembly body 9 to movement within an axial planeand limiting both translation and rotation in the plane.

As shown in FIG. 3, the linkage mount 12, the rear backside link 17, therear plate side link 16 and the rear mounting link 15 are assembled bythe use of hinge pins 18. The back bar assembly is integral to themagnetic assembly body of the vehicle with bolts passing through boltholes located at the front of the front linkage mount 13 and the rearmounting link 15.

The exact dimensions of the back bar will vary depending upon the sizeof the inspection vehicle. As the size of the vehicle varies, the numberof back bars will increase for larger vehicles or decrease for smallervehicles. The shape of the magnetic back bar linkage mount 12 matchesthe shape and dimensions of the back bar 11.

As shown in FIG. 4, the front end of the linkage system comprises threeinterlocking links joined by hinge pins 18 at the front end of themagnetic back bar linkage mount 12, both ends of the front mid link 14and the rear end of the magnetic back bar linkage mount 13. The hingepins 18 are then held in place by the locking snap rings 19.

As shown in FIG. 5, the rear end of the linkage system comprises fourinterlocking links joined by hinge pins 18 at the rear end of themagnetic back bar linkage mount 12, both ends of the rear backside link17, both ends of the rear plate side link 16, and at the top of the rearmounting link 15. Again, as in the front end of the linkage assembly,the hinge pins 18 are held in place by the locking snap rings 19.

1. A linkage for supporting the elements of an instrument pig,comprising: a back bar assembly; a front linkage connected to saidinstrument pig and said back bar assembly; and a rear linkage connectedto said instrument pig and said back bar assembly.
 2. The instrument pigof claim 1, wherein said instrument pig is used for the in-lineinspection of a pipeline.
 3. The front linkage of claim 1, wherein saidfront linkage comprises multiple links.
 4. The front linkage of claim 3,wherein said front linkage comprises two links.
 5. The rear linkage ofclaim 1, wherein said rear linkage comprises multiple links.
 6. The rearlinkage of claim 5, wherein said rear linkage comprises three links. 7.The rear linkage of claim 6, wherein said rear linkage allows said backbar assembly to stay parallel to the inside surface of said pipeline assaid instrument pig moves through the interior of said pipeline.
 8. Therear linkage of claim 7, wherein said rear linkage restricts saidinstrument pig to movement within an axial plane of said pipeline.